Some of the possible fields of application of the process according to the invention are the following:
the production of nanometer-size electrodes by using solutes capable of conducting electric current (e.g. metals in colloidal suspension, conducting polymers and molecules, coordination compounds, et cetera);
the production of micro- and nanostructured devices by using “electroactive” materials (i.e., materials having particular electrical properties, e.g. organic and polymeric semiconductors);
the anisotropic or isotropic molding of material deposited on any thin film, substrate and/or device;
the local etching and/or direct patterning of a substrate by using solutions that are reactive with respect to the substrate;
the transfer of periodic patterns that leads to the manufacture of arrays useful for photonics or for creating templating substrates;
the manufacture of rewritable and non-rewritable memory elements;
the forming of supramolecular systems (for example, directed assembly of oriented fibrils of conjugated molecules) by exploiting the self-organization properties of a solute.
Among non-conventional methods (i.e., methods alternative to those based on photolithographic processes) for manufacturing electrodes, patterns and structures with periodic and nonperiodic features, contact printing and nanoimprinting (embossing) are among the most promising, particularly for manufacturing organic integrated circuits. This is due to the simplicity of the approach, the limited number of processes involved, the low requirements in terms of energy, cleanliness of the environment and chemical reagents, the potential to upscale the printing process in a form that is cyclic, automated and repeatable a large number of times, et cetera. These methods, described for example in Chou, U.S. Pat. No. 5,772,905, dated Jun. 30, 1998 and entitled “Nanoimprint lithography” and in Whitesides et al., U.S. Pat. No. 5,900,160, dated May 4, 1999 and entitled “Methods of etching articles via microcontact printing”, are used to imprint nanometer-sized structures directly on a film of polymeric material, or to deposit a resist thin film with submicrometer spatial definition. The printed materials are then subjected to a developing process and to several subsequent steps (e.g. lift-off, deposition of the material of interest on the mask) in order to form the printed pattern of the relevant material (which is generally different from the printed material). In the field of nanotechnology research, the European Union has allocated 1300 million euros in the Sixth Framework Programme, started in 2003.
The success of a technology depends not only on the particular properties of the processed material and of the device but also on its effectiveness, simplicity and cost.
The aim of the present invention is to provide a printing process that allows to manufacture, manipulate and organize a variety of soluble materials (e.g. molecules, macromolecules, polymers, colloids) with downscaling of the dimensions of the patterns that are present on the stamp used. Such a process is also suitable for facilitating chemical reactions, or to promote re-organization processes (such as re-crystallisation, dewetting) that occur in small volumes (picoliters).
Other objects of the invention are:
to provide a process that can be performed on a large scale, is repeatable for a large number of cycles, and can be engineered in an existing and commercially viable manufacturing technology;
to provide a process that allows to manufacture, modify, improve, manipulate and give organization and structural order of the molecules of a thin film of soluble materials, with a spatial resolution from one micrometer to tens of nanometers;
to provide a process for manufacturing thin films of conjugated materials with specific properties of anisotropy of structural, electrical, optical and optoelectronic properties that is effective and simple and has low production costs.
This aim and these and other objects that will become better apparent from the description that follows are achieved by a process as defined in the claims.